IMHO thats the best camera out there (sx10IS) that falls into the "super Zoom" camera. the D5000 is IMHO a souped up D40 with some of the controls of the D90....but 300.00 more than a D40 with no lens. It does have a GEN 2 processor which means you can change Kelvin settings for WB adjustments...also you can make nice enlargements of 30x40. If I where going to spend 700.00+ for a camera, I'd spend a few hundred more and get the D90. Most places dont carry the D40 anymore, because the salesmen want you to spend more and get the D40x, D80, D5000. You wont see any difference in image quality from a 6MP camera compared to a 12MP camera in enlargements of 16x20 and below. The D40 really shines at higher ISOs, at 800, its better than many. Plus you can flash sync at 1/500, which is great for portraits outdoors....the flash sync with the D5000 and even d90 is 1/200.
to me its a no brainer....if spending 900.00 or less, get the D40, over 900.00...get the D90
I paid 600.00 for my D40 when it came out 2 years ago....you can get 1 now for 429. which includes a nice kit lens, plus case and card....use the extra money and get the real nice 55-200 VR for 200.00 bucks or the great little 35mm 1.8 for the same price for available light pics.
http://www.adorama.com/INKD40KH.html

adorama or B&H photo are reliable places to order from...what sold me on Nikon is there 5 year warranty on lenses
If you do end up with a D40, email me and I'll give you some tricks about using the camera, like a secert RGB color histogram, etc
NICE SHOTS BTW